Thermal kinetic studies, denaturation studie

T. Le Bihan and C. Gicquaud, Kinetic study of the thermal denaturation of G actin using differential scanning calorimetry and intrinsic fluorescence spectroscopy, Biochem. Biophys. Res. Commun. 194, 1065-1073 (1993). 

Steady-state kinetics studies of the inhibition of the enzyme by oxR-mate and oxalate 203) hinted at the existence of enzyme-oxamate complexes. No binding of 0.15 milf oxamate was detected in the ultracentrifuge. However, Siidi 283) reported that oxalate (15 mM) and oxamate (60 mM) protect M4 enzyme from heat denaturation. Oxaloacetate and fructose 1,6-diphosphate are effective at protecting against thermal denaturation at 1 mM concentration 286). It is possible that these anions bind at sites similar to those detected in the dogfish M4 LDH molecule 139). 

Galisteo M L, Mateo P L, Sanchez-Ruiz J M (1991). Kinetic study on the irreversible thermal denaturation of yeast phosphoglycerate kinase. Biochem. 30(8) 2061-2066. 

In an analogous way the influence of alcohol on the kinetics of thermal denaturation of met-hemoglobin was studied successfully144). 

We studied the effects of total and partial deuteration on the kinetics of thermal denaturation of met-hemoglobin. The kinetics were shown to be first order with respect to protein concentration this was true both in H2O and in D2O within the entire range of temperatures examined. Deuterium oxide increased the stability of the native conformation of met-hemoglobin this effect increased progressively by increasing the amount of D2O in the solution. Extension of the experiments to the amplest possible temperature range (50-63°C) allowed the determination of the isotopic effect on the activation enthalpy and entropy of the denaturation reaction the isotopic effect resulted to be mainly entropic. 

Through calorimetric studies, Privalov showed that thermal denaturation of porcine pepsin is a complex process that proceeds by two distinct stages occurring at different temperatures. Because pepsin has been well structurally characterized, it represents an appropriate model to study the effects of metal ions on structure, function and kinetic behaviour (Privalov et al. 1981). 

Bamase, like CI2, has been the subject of extensive studies, using the protein engineering method combined with kinetic and equilibrium experiments, to investigate its fold-ing/unfolding pathway." Molecular dynamics simulations of thermal denaturation of the wild-type and two mutant proteins (Tyr 17 —> Gly and He 88 —> Val) have been performed to investigate the effect of mutations on the unfolding pathway and transition state." ... 

A retardation in the rate of denaturation of a pure protein in solution, comparable to the pressure effect on the thermal destruction of the luminescent system, thus assumes particular interest. Qualitative observations have recently shown that this phenomenon takes place in solutions of highly purified egg albumin and serum globulin (120). A pressure of 10,000 lb. per sq. in. practically pi events the precipitation of the latter protein at 65°C. and pH near neutrality. Quantitative studies of the kinetics of this denaturation have not been completely analyzed, but the indications are that a volume increase of activation on the order of 100 cc. per mole is involved (121). Small concentrations of ethyl alcohol accelerate the precipitation under both normal and increased pressure, as shown in Figure 17 the denaturation proceeds with a large volume increase of activation, of the order of 100 cc. per mole, as in the destruction of the... 

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